1. Field of the Invention
The field of art to which this invention pertains may be generally located in the class of devices relating to valves. Class 137, Fluid Handling, Subclass 318 United States Patent Office Classification, appears to be the applicable general area of art to which the subject matter similar to this invention has been classified in the past.
2. Description of the Prior Art
It is necessary in many instances to terminate the flow of fluid through a fluid flow system, such as a gas line or a liquid line, because of a a failure in the fluid flow system due to a leaking valve, a crack in the fluid flow line, or other problems which require the fluid flow system to be shut down to make the required repairs. It is also necessary in many instances, because of required maintenance or changes in a water system, a refrigeration system, an air conditioning system and other fluid flow systems to temporarily shutdown such systems for many hours. Such problems can involve the loss of many work hours, and the closing of buildings containing fluid flow systems wherein the flow of fluid therethrough must be terminated for either a short period or a long period.
Heretofore it has been proposed to provide a valve insertable in a fluid flow line which could be attached to the fluid flow line and which included a hole cutter means for cutting a hole through the fluid flow line and placing a tubular seal in the hole to block the flow of fluid downstream of the blocked hole. Such an in-line insertable valve is disclosed and described in U.S. Pat. No. 5,316,037.
The valve disclosed in U.S. Pat. No. 5,316,037 has proved in use that it is constructed and arranged for efficient insertion into a pressurized fluid flow line comprising copper tubing. However, experience has shown that a heavier duty valve with an improved cutting structural arrangement is preferable when there is a need to insert an in-line valve into a pressurized fluid flow line comprising steel pipe and plastic pipe.